CentOS simple remote dedicated server transfer to a Debian home machine
I wish to transfer a CentOS dedicated remote server (one perl oriented HTML site plus 100s of research-exploration µ-mediawikis) to a home Debian machine. Is there a simple and reliable typical solution to that?
All Distros are roughly the same.
There are many approaches, here's how I do this.
1) Setup Ubuntu + LXD at machine level.
2) Each Site/App/API gets their own LXD container, which makes moving system trivial...
3) If code is fairly simple + self-contained...
a) Run mysqldump to dump all related databases into the site's DocumentRoot.
b) Then rsync the entire DocumentRoot to new machine (Ubuntu, CentOS, Alpine, whatever).
c) Restore database.
d) Setup HTTPS + HTTP2 + Brotli + bring up site.
4) If machine code has been hacked... er I mean heavily modified by developers for decades, just trying to understand what to move can be near impossible... then the result is a massively unstable or crashing new install.
To handle this type of config I use https://discuss.linuxcontainers.org/t/howto-use-lxd-p2c/3574 which is highly addictive.
The handle lxd-p2c tool clones an entire machine into an LXD container... bit for bit... producing an exact + running replica of the machine.
The only caveat using this tool is to pause any SQL daemon or any other code which maintains any memory state.
By pausing MariaDB/MySQL/Oracle/Postg
Missing this step almost always caused data corruption + certainly data loss.
An alternative to... production sites, which can only tolerate a few seconds of outage is to...
a) Run lxd-p2c once.
b) Pause SQL daemons on both source + target machine.
c) The rsync raw files across, for example /var/lib/mysql, for MariaDB/MySQL.
d) Then restart target machine.
In most cases this can be done so only a few seconds of outage time occurs.
There are many approaches, here's how I do this.
1) Setup Ubuntu + LXD at machine level.
2) Each Site/App/API gets their own LXD container, which makes moving system trivial...
lxc move cname new-machine:new-cname3) If code is fairly simple + self-contained...
a) Run mysqldump to dump all related databases into the site's DocumentRoot.
b) Then rsync the entire DocumentRoot to new machine (Ubuntu, CentOS, Alpine, whatever).
c) Restore database.
d) Setup HTTPS + HTTP2 + Brotli + bring up site.
4) If machine code has been hacked... er I mean heavily modified by developers for decades, just trying to understand what to move can be near impossible... then the result is a massively unstable or crashing new install.
To handle this type of config I use https://discuss.linuxcontainers.org/t/howto-use-lxd-p2c/3574 which is highly addictive.
The handle lxd-p2c tool clones an entire machine into an LXD container... bit for bit... producing an exact + running replica of the machine.
The only caveat using this tool is to pause any SQL daemon or any other code which maintains any memory state.
By pausing MariaDB/MySQL/Oracle/Postg
Missing this step almost always caused data corruption + certainly data loss.
An alternative to... production sites, which can only tolerate a few seconds of outage is to...
a) Run lxd-p2c once.
b) Pause SQL daemons on both source + target machine.
c) The rsync raw files across, for example /var/lib/mysql, for MariaDB/MySQL.
d) Then restart target machine.
In most cases this can be done so only a few seconds of outage time occurs.
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In fact based upon your advices I am engaged into a step by step "a side" rebuild. Mail system, Apache system, MediaWiki system, etc. tuning the new server to an adequate config (config files). Then I plan to take advantage from the acquired experience to develop a "winux" management solution that will be able to carry the job next time and keep the things and my operations running. In the process I discovered the work of investigation on the "smart internet" architecture, that could help me tying together with other winuxers. I will keep this ticket posted of my endeavors.
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I have no idea yet of what lxd-p2c may be, but I will learn. I never understood yet how container are actually built: this will be a good occasion of doing it !
Deep thx !
Deep thx !
You're welcome!
lxd-p2c docs provides a starting point.
Beware though...
Using lxd-p2c can be addictive, if you have to move old/undocumented physical machines. :-)
lxd-p2c docs provides a starting point.
Beware though...
Using lxd-p2c can be addictive, if you have to move old/undocumented physical machines. :-)
1) CentOS runs a very old Kernel, even most recent CentOS.
2) All your config files will be different in CentOS + Debian.
3) If you require a recent Kernel, use Ubuntu instead of CentOS.
3) And whatever you choose the simple solution... in next comment...